CN114337851A - Intelligent super-surface assisted terahertz secure communication method and device - Google Patents

Intelligent super-surface assisted terahertz secure communication method and device Download PDF

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CN114337851A
CN114337851A CN202111570597.XA CN202111570597A CN114337851A CN 114337851 A CN114337851 A CN 114337851A CN 202111570597 A CN202111570597 A CN 202111570597A CN 114337851 A CN114337851 A CN 114337851A
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idr
ehr
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terahertz
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朱政宇
徐金雷
梁静
孙钢灿
王忠勇
郝万明
巩梦飞
李铮
杨晨一
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Zhengzhou University
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Abstract

The invention relates to an intelligent super-surface assisted terahertz secure communication method and device, wherein the method comprises the following steps: establishing an intelligent super-surface assisted terahertz wireless energy-carrying transmission safety communication system model under a nonlinear energy collection model; assuming that the system does not have complete cascade channel state information, under the constraint of interruption probability, a robust beam forming design scheme is provided by jointly optimizing active and passive beam forming, and the minimum of system transmitting power is realized; the method comprises the steps of converting interruption probability constraint into a deterministic form by using a Bernstein-type inequality, converting an original non-convex problem into a convex problem by using a semi-deterministic planning method, and providing an alternative iterative optimization algorithm to obtain a feasible solution of the original problem. The method combines the intelligent super-surface and the terahertz communication technology, researches the robust safe transmission of the terahertz system based on the intelligent reflecting surface assisted nonlinear energy acquisition, and improves the safety of the communication system by jointly optimizing the transmitting beam forming matrix and the intelligent super-surface phase shift matrix under the condition of meeting the system energy acquisition.

Description

Intelligent super-surface assisted terahertz secure communication method and device
Technical Field
The invention belongs to the technical field of communication, and particularly relates to an intelligent super-surface assisted terahertz secure communication method and device.
Background
The future wireless communication (B5G/6G) aims to establish higher performance indexes, introduce new application scenarios and accelerate the digitization of the society. In order to meet the requirement of emerging applications for ultra-high data rates, terahertz (THz) wireless communication technology is receiving wide attention from both academic and industrial fields. THz can realize wireless transmission of up to 1Tbps, and can solve the problems of insufficient frequency spectrum and capacity limitation of the existing wireless system.
Recently, smart super surfaces (RIS) is a uniform array plane integrating a large number of passive reflective elements, and is considered one of the most promising technologies in future wireless communications. By adjusting the amplitude and the phase of the element, the transmission direction of the signal is skillfully changed, and the strength of the received signal is effectively enhanced. The RIS is applied to the THz communication, a virtual direct connection link can be established, the signal receiving is effectively improved, and the probability of signal blocking is reduced.
Future large-scale access of 6G network devices will inevitably bring about information security issues and a dramatic increase in energy consumption. How to realize high-speed and low-power-consumption data secure transmission becomes the key of future networks. Meanwhile, wireless energy-carrying communication (SWIPT) effectively provides energy for various terminal devices by extracting energy in received signals. In addition, the active and passive interactive transmission technology based on the RIS can ensure the safety of the physical layer information transmission and improve the receiving power of the desired signal. Therefore, the method has important theoretical significance and practical value in consideration of the physical layer safety problem by combining the SWIPT and the RIS auxiliary THz communication system.
Furthermore, the RIS is composed of passive components, and is neither able to transmit nor receive pilot symbols. Therefore, considering incomplete Channel State Information (CSI) is more reasonable and effective, and is practical. The invention provides a robust beamforming design scheme of a RIS-assisted safe SWIPT THz communication system.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides an intelligent super-surface assisted terahertz safe communication method and device.
The purpose of the invention is realized as follows: an intelligent super-surface assisted terahertz secure communication method comprises the following steps:
s1: establishing an intelligent super-surface assisted terahertz wireless energy-carrying transmission safety communication system model under a nonlinear energy collection model;
s2: assuming that the system does not have complete cascade channel state information, under the constraint of interruption probability, a robust beam forming design scheme is provided by jointly optimizing active and passive beam forming, and the minimum of system transmitting power is realized;
Figure BDA0003423579010000021
Figure BDA0003423579010000022
Figure BDA0003423579010000023
Figure BDA0003423579010000024
Figure BDA0003423579010000025
wherein the content of the first and second substances,
Figure BDA0003423579010000026
is the transmit beamforming vector from the AP to the mth IDR,
Figure BDA0003423579010000027
is the signal-to-noise ratio of the mth IDR,
Figure BDA0003423579010000028
is the signal-to-noise ratio, μ, of the kth EHR intercepting the first IDR informationminIs the minimum signal-to-noise ratio, γ, required for IDRminIs the minimum signal-to-noise ratio threshold, R (p), for the EHR to successfully decode the informationk) Is the minimum threshold for non-linear energy harvesting,
Figure BDA0003423579010000029
representing the maximum outage probability satisfying constraints (1b), (1c) and (1d), the phase shift matrix of the RIS being defined as
Figure BDA00034235790100000210
θn∈(0，2π]，NRISIs the number of elements of the RIS;
s3: the method comprises the steps of converting interrupt constraint into a deterministic form by using a Bernstein-type inequality, converting an original non-convex problem into an equivalent convex problem by using a semi-deterministic planning method, and providing an alternative iterative optimization algorithm to obtain a feasible solution of the original problem.
The step S1 specifically includes:
a THz safe SWIPT system based on RIS assistance is established,the system comprises an NTXAP of root antenna, one configuration NRISThe RIS of the individual reflection units, the IDRs of the M individual antennas and the EHRs of the K individual antennas, and further, the controller is connected to the RIS and the AP to acquire phase information required for the RIS, and all receivers can receive only the reflected signal of the RIS provided that the direct link from the AP to the IDR/EHR is blocked by an obstacle.
The step S2 specifically includes:
due to the passive characteristic of the RIS, complete CSI is very difficult to obtain in an actual SWIPT system, so that the consideration of incomplete CSI is more reasonable and effective in a cascade channel AP-RIS-IDR/EHR, and the method is in line with the reality. In the invention, a statistical CSI error model which has a closer relation with a channel estimation error is adopted, and the aim is to realize the minimization of the total emission of the system by jointly optimizing active and passive beam forming under the constraints of signal-to-noise ratios of IDR and EHR and the interruption probability of nonlinear energy acquisition.
The step S3 specifically includes:
in view of the non-convexity of the original optimization problem, the invention adopts a Bernstein-type inequality to convert the signal-to-noise ratio of IDR and EHR and the interruption probability constraint of nonlinear energy acquisition into a linear matrix inequality form. In addition, an alternative optimization method based on a semi-definite relaxation technology is utilized to obtain a feasible solution of the problem.
An intelligent super-surface auxiliary terahertz safety communication device comprises
The model establishing module is used for establishing an intelligent super-surface assisted terahertz wireless energy-carrying transmission safety communication system model under the nonlinear energy collection model;
an equation construction module, which provides a robust beam forming design scheme by jointly optimizing active and passive beam forming under the constraint of interruption probability and realizes the minimization of system transmitting power on the assumption that the state information of the cascade channel is incomplete;
Figure BDA0003423579010000041
Figure BDA0003423579010000042
Figure BDA0003423579010000043
Figure BDA0003423579010000044
Figure BDA0003423579010000045
wherein the content of the first and second substances,
Figure BDA0003423579010000046
is the transmit beamforming vector from the AP to the mth IDR,
Figure BDA0003423579010000047
is the signal-to-noise ratio of the mth IDR,
Figure BDA0003423579010000048
is the signal-to-noise ratio, μ, of the kth EHR intercepting the mth IDR informationminIs the minimum signal-to-noise ratio, γ, required for IDRminIs the minimum signal-to-noise ratio threshold, R (p), for the EHR to successfully decode the informationk) Is the minimum threshold for non-linear energy harvesting,
Figure BDA0003423579010000049
representing the maximum outage probability satisfying constraints (2b), (2c) and (2d), the phase shift matrix of the RIS being defined as
Figure BDA00034235790100000410
θn∈(0，2π]，NRISThe number of reflection units of the RIS.
And the iteration solving module is used for converting the interruption constraint into a deterministic form by using a Bernstein-type inequality, converting the original non-convex problem into an equivalent convex problem by using a semi-deterministic planning method, and providing an alternative iteration optimization algorithm to obtain a feasible solution of the original problem.
The model building module specifically comprises:
establishing a RIS-assisted THz safe SWIPT system, which comprises an NTXAP of root antenna, one configuration NRISRIS of individual reflector units, IDRs of M individual antennas and EHRs of K individual antennas. In addition, the controller is connected to the RIS and the AP to acquire phase information required for the RIS. Assuming that the direct link from the AP to the IDR/EHR is blocked by an obstacle, all receivers can only receive the reflected signal of the RIS.
The equation constructing module specifically comprises:
the equation building block, due to the passive nature of RIS, makes it very difficult to obtain perfect CSI in a practical SWIPT system. Therefore, in the cascaded channel AP-RIS-IDR/EHR, the consideration of incomplete CSI is more reasonable and effective, and the method is in line with the reality. In the invention, a statistical CSI error model which has a closer relation with a channel estimation error is adopted, and the aim is to realize the minimization of the total transmission power of the system by jointly optimizing active and passive beam forming under the constraints of signal-to-noise ratios of IDR and EHR and the interruption probability of nonlinear energy acquisition.
The iterative solution module specifically includes:
in view of the non-convexity of the original optimization problem, the iterative solution module adopts a Bernstein-type inequality to convert the signal-to-noise ratio of IDR and EHR and the interruption probability constraint of nonlinear energy acquisition into a linear matrix inequality form. In addition, an alternative optimization method based on a semi-definite relaxation technology is utilized to obtain a feasible solution of the problem.
Drawings
Fig. 1 is a schematic structural diagram of an intelligent super-surface assisted terahertz secure communication method provided by the invention.
Fig. 2 is a schematic structural diagram of a RIS-assisted THz SWIPT system model.
FIG. 3 shows a graph of the iterative variation of the proposed algorithm under different channel errors;
FIG. 4 is a graph of total transmit power versus target SNR for the desired IDR/HER;
FIG. 5 shows a graph of total emitted power of the system versus the number of RIS reflecting elements;
FIG. 6 is a schematic structural diagram of an intelligent super-surface assisted terahertz safety communication device provided by the invention;
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without making any creative effort, shall fall within the protection scope of the present invention.
The invention provides an intelligent super-surface assisted terahertz safe communication method and device. Assuming that the state information of the cascade channel is not complete, under the constraint of interruption probability, a robust beam forming design scheme is provided by jointly optimizing active and passive beam forming, and the minimization of the total transmission power of the system is realized.
As shown in fig. 1, the method comprises the steps of:
s1: establishing an intelligent super-surface assisted terahertz wireless energy-carrying transmission safety communication system model under a nonlinear energy collection model;
s2: assuming that the system does not have complete cascade channel state information, under the constraint of interruption probability, through jointly optimizing active and passive beam forming, a robust beam forming design is provided to minimize the total transmitting power of the system;
s3: the method comprises the steps of converting interruption probability constraint into a deterministic form by using a Bernstein-type inequality, converting an original non-convex problem into a convex problem by using a semi-deterministic planning method, and providing an alternative iterative optimization algorithm to obtain a feasible solution of the original problem.
As shown in fig. 2, the method described in this embodiment is applied to a RIS-assistance-based THz-safe swapt system. In the present invention, random phase shift is usedLine Performance comparison, for statistical CSI error model, EmIs defined as
Figure BDA0003423579010000061
Wherein
Figure BDA0003423579010000062
And
Figure BDA0003423579010000063
also, in the same manner as above,
Figure BDA0003423579010000064
is defined as
Figure BDA0003423579010000065
Wherein
Figure BDA0003423579010000066
And
Figure BDA0003423579010000067
εmand
Figure BDA0003423579010000068
is the relative quantity that the normalized CSI error uses to measure the CSI uncertainty
Figure BDA0003423579010000069
For the nonlinear wireless EH model, x-28 dBm, Z-24 mW, a-150, and b-0.024 are set. Other simulation parameters are shown in table 1:
TABLE 1 System simulation parameters
Figure BDA00034235790100000610
In this embodiment, the specific process of step S1 is as follows:
establishing a RIS-assisted THz safe SWIPT system, which comprises an NTXAP of root antenna, one configuration NRISRIS of individual reflecting units, M single daysThe IDR of the line and the EHR of the K single antennas, in addition, the controller is connected to the RIS and AP to obtain the phase information required by the RIS, assuming that the direct link from the AP to the IDR/EHR is blocked by the wall, all receivers can only receive the reflected signal of the RIS.
The mth IDR received signal is expressed as
Figure BDA0003423579010000071
Wherein the content of the first and second substances,
Figure BDA0003423579010000072
represents the equivalent channel from the RIS to its mth IDR,
Figure BDA0003423579010000073
represents the equivalent channel from the AP to the RIS,
Figure BDA0003423579010000074
is the transmit beamforming vector from the AP to the mth IDR,
Figure BDA0003423579010000075
it represents that the complex gaussian random variables are independently and equally distributed,
Figure BDA0003423579010000076
equal to Additive White Gaussian Noise (AWGN). The RIS phase shift matrix is defined as
Figure BDA0003423579010000077
θn∈(0，2π]。
Furthermore, given that the THz scattering power is much lower than the line-of-sight component, the present invention only considers the line-of-sight component
Figure BDA0003423579010000078
Wherein the content of the first and second substances,
Figure BDA0003423579010000079
c denotes the speed of light, f denotes the center frequency,. tau. (f) denotes the medium absorption factor, and d denotes the distance from AP to RIS.
Figure BDA00034235790100000710
Will be provided with
Figure BDA00034235790100000711
And
Figure BDA00034235790100000712
as antenna array response vectors for the transmitter and receiver, respectively
Figure BDA00034235790100000713
Figure BDA00034235790100000714
Wherein the content of the first and second substances,
Figure BDA00034235790100000715
i＝[r,t]，d0represents the distance between the antennas, andi∈[-π/2,π/2]angle of departure (AOD) and angle of arrival (AOA). Also, the same applies to
Figure BDA00034235790100000716
Wherein the content of the first and second substances,
Figure BDA0003423579010000081
and
Figure BDA0003423579010000082
dI,mis the distance between the RIS and the mth IDR.
Definition of
Figure BDA0003423579010000083
Cascade AP-RIS-IDRmThe following formula is used for the channelTo represent
Figure BDA0003423579010000084
Wherein the content of the first and second substances,
Figure BDA0003423579010000085
satisfy the requirement of
Figure BDA0003423579010000086
Defining η as a path compensation factor, and rewriting (1) to (2) to (6)
ym＝βm(θHGI,mwmsm)+n0, m＝1,...,M, (7)
Wherein, betam＝ηGtGrq(f,d)q(f,dI,m). The signal-to-noise ratio of the mth IDR is
Figure BDA0003423579010000087
Thus, the received power of the kth EHR may be expressed as
Figure BDA0003423579010000088
Where ξ, the efficiency of harvesting energy, representing the equivalent channel from RIS to the kth EHR, is similar to equation (5), one can obtain
Figure BDA0003423579010000089
Wherein the content of the first and second substances,
Figure BDA00034235790100000810
and
Figure BDA00034235790100000811
dE,krepresents the distance between RIS and the kth EHR. Cascade channel AP-RIS-EHRkCan be expressed as
Figure BDA00034235790100000812
Wherein the content of the first and second substances,
Figure BDA00034235790100000813
and
Figure BDA00034235790100000814
calculated according to (10) and (11) and (9) as
Figure BDA00034235790100000815
To accurately characterize EH, the present invention employs a nonlinear EH model based on actual measurements. Therefore, the temperature of the molten metal is controlled,
the energy collected by the EHR is represented by the following equation
Figure BDA0003423579010000091
Wherein Z represents the maximum output DC power, a and b are constants associated with actual circuit specifications, and X and Y are defined as
Figure BDA0003423579010000092
And
Figure BDA0003423579010000093
in addition, the EHR may serve as a potential eavesdrop in the present invention.
Signal-to-noise ratio of received kth EHR
Figure BDA0003423579010000094
Due to the passive nature of RIS, it is very difficult to obtain perfect CSI in a practical SWIPT system. Therefore, in the cascaded channel AP-RIS-IDR/EHR, the consideration of incomplete CSI is more reasonable and effective, and the method is in line with the reality. The invention adopts a statistical CSI error model with a more close channel estimation error relationship.
Assuming that the concatenated channels from AP to mth IDR and from AP to kth EHR are not perfect, they may be expressed as
Figure BDA0003423579010000095
Figure BDA0003423579010000096
Wherein the content of the first and second substances,
Figure BDA0003423579010000097
is the channel estimation error matrix for the mth IDR,
Figure BDA0003423579010000098
also, in the same manner as above,
Figure BDA0003423579010000099
is the CSI vector for the kth EHR,
Figure BDA00034235790100000910
from equations (15) and (16), equations (8) and (14) can be rewritten as
Figure BDA00034235790100000911
Figure BDA00034235790100000912
In the invention, the transmission beam forming vector is optimized in a combined manner, and the minimum signal-to-noise ratio requirements of IDR and EHR are met under the constraint of RIS reflection phase shift, so that the minimum system transmission power is realized. Expressing the original problem as
Figure BDA0003423579010000101
Figure BDA0003423579010000102
Figure BDA0003423579010000103
Figure BDA0003423579010000104
Figure BDA0003423579010000105
Wherein, muminIs the minimum signal-to-noise ratio requirement and gamma of the IDRminA minimum signal-to-noise threshold representing an EHR that successfully decodes the information.
Figure BDA0003423579010000106
Denotes the maximum probability of interruption, p, that satisfies the constraints (19b), (19c) and (19d), respectivelykIs the minimum energy harvesting requirement. R is R0(pk) Inverse function of, R (p)k) Represents
Figure BDA0003423579010000107
When (19b) and (19c) are satisfied at the same time, the minimum IDR security information rate can be ensured. Problem (19) is a non-convex problem that is difficult to solve due to complex probabilistic constraints. Thus, applying the Bernstein-type inequality converts the probabilistic constraint into a deterministic form. First, redefine (19b) as
Figure BDA0003423579010000108
Definition of
Figure BDA0003423579010000109
By using identity aHBa＝Tr(BaaH) Change (21) into
Figure BDA00034235790100001010
Definition of
Figure BDA00034235790100001011
According to the equation
Figure BDA00034235790100001012
Convert (22) into
Figure BDA00034235790100001013
Definition of
Figure BDA00034235790100001014
And
Figure BDA00034235790100001015
constraint (19b) to
Figure BDA00034235790100001016
Wherein the content of the first and second substances,
Figure BDA0003423579010000111
the present invention employs the following process to handle probabilistic signal-to-noise ratio constraints.
Introduction 1: (Bernstein-type inequality): definition of
Figure BDA0003423579010000112
And
Figure BDA0003423579010000113
for any 0<ρ ≦ 1, considering the following inequality
pr{(eHQe)+2Re(eHr)+χ≥0}≥1-ρ. (25)
Transforming (25) into the form:
Figure BDA0003423579010000114
wherein, t1And t2Are all relaxation variables. Using theorem 1, the probabilistic constraint (24) can be rewritten as
Figure BDA0003423579010000115
Wherein the content of the first and second substances,
Figure BDA0003423579010000116
and
Figure BDA0003423579010000117
is the relaxation variable. In the same way, define
Figure BDA0003423579010000118
And
Figure BDA0003423579010000119
the constraint (19c) becomes
Figure BDA00034235790100001110
Wherein the content of the first and second substances,
Figure BDA00034235790100001111
according to the introduction 1, rewrite (28) to
Figure BDA00034235790100001112
Wherein the content of the first and second substances,
Figure BDA00034235790100001113
and
Figure BDA00034235790100001114
is the relaxation variable.
Definition of
Figure BDA0003423579010000121
And
Figure BDA0003423579010000122
(19d) is converted into
Figure BDA0003423579010000123
Wherein the content of the first and second substances,
Figure BDA0003423579010000124
similarly, (30) can be converted into
Figure BDA0003423579010000125
Wherein the content of the first and second substances,
Figure BDA0003423579010000126
and
Figure BDA0003423579010000127
is the relaxation variable.
Introducing a new variable
Figure BDA0003423579010000128
And rewriting the question (19) as
Figure BDA0003423579010000129
s.t.(27),(29),(31), (32b)
Figure BDA00034235790100001210
Figure BDA00034235790100001211
Figure BDA00034235790100001212
Figure BDA00034235790100001213
Figure BDA00034235790100001214
However, due to the variable WmAnd
Figure BDA00034235790100001215
the problem (32) is still not convex and is difficult to solve directly. A. Give a
Figure BDA00034235790100001216
Solving a beamforming matrix Wm
A sub-optimal solution of the non-convex problem (32) of variable coupling is obtained using the AO algorithm. When in use
Figure BDA00034235790100001217
When the variable W is given, the solution variable W can be solved by adopting the SDR technologym. Removing the rank-one constraint (32d), the problem (32) translates into
Figure BDA00034235790100001218
s.t.(27),(29),(31),(32c) (33b) wherein, in the above-mentioned step,
Figure BDA0003423579010000131
the problem (33) can be computed by applying a convex problem solver, such as the CVX tool box. However, the resulting solution cannot be guaranteed
Figure BDA0003423579010000132
A rank-one constraint is satisfied. Therefore, the following theorem is given to illustrate that the proposed algorithm satisfies the rank-one constraint.
Theorem 1: if the problem (33) can be solved using SDR techniques, then there is always a feasible solution defined as
Figure BDA0003423579010000133
Satisfy the requirement of
Figure BDA0003423579010000134
m∈M。
Proving of definition
Figure BDA0003423579010000135
Is an optimal solution to the problem (33) and defines a projection matrix
Figure BDA0003423579010000136
Wherein the content of the first and second substances,
Figure BDA0003423579010000137
furthermore, a rank-one solution to the problem (33) is constructed
Figure BDA0003423579010000138
Each sub-matrix is represented as
Figure BDA0003423579010000139
Comparing the target value of the problem (33) construction with the actual optimal solution
Figure BDA00034235790100001310
Can obtain the solution of the original structure problem
Figure BDA00034235790100001311
The value of the objective function is not larger than the actual optimal solution
Figure BDA00034235790100001312
The generated value. However, it is still computationally difficult to directly judge
Figure BDA00034235790100001313
Whether or not (27) is satisfied. Therefore, considering the constraint (19b) of the original non-convex problem, according to (33), it is possible to obtain
Figure BDA00034235790100001314
Figure BDA00034235790100001315
Combining (37) and (38) to obtain
Figure BDA0003423579010000141
According to (36) and (39), checking
Figure BDA0003423579010000142
Is a locally optimal solution of the problem (33) of rank one. B. Solving for the reflection phase shift matrix of the RIS
When the problem (33) is solved
Figure BDA0003423579010000143
Problem (32) becomes a feasibility verification problem. However, due to constraints
Figure BDA0003423579010000144
Reflection matrix
Figure BDA0003423579010000145
It is difficult to solve directly by CVX. Using SDR techniques, the constraint (32g) is removed and the RIS phase shift is obtained by the following problem
Figure BDA0003423579010000146
s.t.(27),(29),(31),(32e),(32f). (40b)
A locally optimal solution to the problem (34) is found using the CVX tool box. Since (32g) is removed from the problem (40), the solution obtained using eigenvalue decomposition cannot guarantee a rank of one. Thus, a high quality rank-one solution to the problem (40) is recovered using a standard gaussian randomization method.
According to the technical scheme, the intelligent super-surface-assisted terahertz safe communication method is provided, a scheme combining transmit beam forming and phase shift matrix design is researched by introducing a statistical CSI error model, and system transmit power minimization is achieved.
FIG. 3 shows the equation μ min4 and γminWhen the signal channel is equal to 1, under different channel uncertainty conditions, the convergence performance of the method relative to the total transmission power of the system is improved. It can be seen from the results that the convergence speed of the proposed algorithm is relatively fast under different channel error parameters, and the convergence speed does not change with the increase of the estimation error.
Fig. 4 shows the performance of two different methods versus the signal-to-noise ratio of IDR/EHR for different numbers of transmit antennas. (a) And (b) in both cases, the transmit power increases monotonically with increasing signal-to-noise ratio. The transmit power required for the optimized RIS phase shift scheme is significantly lower than for the random phase shift scheme, given the same number of transmit antennas. In addition, more transmit antennas make it easier for the receiver to bring robust beamforming gain and can bring more spatial degrees of freedom to reduce power consumption.
Fig. 5 shows the effect of the number of reflecting elements on the total transmitted power. Obviously, the method provided by the embodiment of the invention is superior to other reference schemes, and the requirement on the total transmission power is smaller and smaller as the number of the reflecting elements is increased. The system acquisition space degree of freedom and the diversity gain are gradually increased along with the increase of the number of RIS reflecting units, thereby realizing higher beam forming gain.
FIG. 6 is a schematic structural diagram of an intelligent super-surface assisted terahertz safety communication device provided by the invention;
the model establishing module is used for establishing an intelligent super-surface assisted terahertz wireless energy-carrying transmission safety communication system model under the nonlinear energy collection model;
an equation construction module, which provides a robust beam forming design scheme by jointly optimizing active and passive beam forming under the constraint of interruption probability and realizes the minimization of system transmitting power on the assumption that the state information of the cascade channel is incomplete;
Figure BDA0003423579010000151
Figure BDA0003423579010000152
Figure BDA0003423579010000153
Figure BDA0003423579010000154
Figure BDA0003423579010000155
wherein the content of the first and second substances,
Figure BDA0003423579010000156
is the transmit beamforming vector from the AP to the mth IDR,
Figure BDA0003423579010000157
is the signal-to-noise ratio of the mth IDR,
Figure BDA0003423579010000158
is the signal-to-noise ratio, μ, of the kth EHR intercepting the mth IDR informationminIs the minimum signal-to-noise ratio, γ, required for IDRminIs the minimum signal-to-noise ratio threshold, R (p), for the EHR to successfully decode the informationk) Is the minimum threshold for non-linear energy harvesting,
Figure BDA0003423579010000159
representing the maximum outage probability satisfying constraints (2b), (2c) and (2d), the phase shift matrix of the RIS being defined as
Figure BDA00034235790100001510
θn∈(0，2π]，NRISThe number of reflection units of the RIS.
And the iteration solving module is used for converting the interruption probability constraint into a deterministic form by using a Bernstein-type inequality, converting the original non-convex problem into a convex problem by using a semi-deterministic planning method, and providing an alternative iteration optimization algorithm to obtain a feasible solution of the original problem.
In this embodiment, the model building module specifically includes:
establishing a RIS-assisted THz safe SWIPT system, which comprises an NTXAP of root antenna, one configuration NRISRIS of individual reflector units, IDRs of M individual antennas and EHRs of K individual antennas. In addition, the controller is connected to the RIS and the AP to acquire phase information required for the RIS. Assuming that the direct link from the AP to the IDR/EHR is blocked by an obstacle, all receivers can only receive the reflected signal of the RIS.
In this embodiment, the equation constructing module specifically includes:
the equation building block, due to the passive nature of RIS, makes it very difficult to obtain perfect CSI in a practical SWIPT system. Therefore, in the cascade channel AP-RIS-IDR/EHR, it is more reasonable and effective to consider incomplete CSI. In the invention, a statistical CSI error model which has a closer relation with a channel estimation error is adopted, and the aim is to realize the minimization of the total transmission power of the system by jointly optimizing active and passive beam forming under the constraints of signal-to-noise ratios of IDR and EHR and the interruption probability of nonlinear energy acquisition.
In this embodiment, the iterative solution module specifically includes:
in view of the non-convexity of the original optimization problem, the iterative solution module adopts a Bernstein-type inequality to convert the signal-to-noise ratio of IDR and EHR and the interruption probability constraint of nonlinear energy acquisition into a linear matrix inequality form. In addition, an alternative optimization method based on a semi-definite relaxation technology is utilized to obtain a feasible solution of the problem.

Claims (8)

1. An intelligent super-surface assisted terahertz secure communication method is characterized by comprising the following steps:
s1: establishing an intelligent super-surface assisted terahertz wireless energy-carrying transmission safety communication system model under a nonlinear energy collection model;
s2: assuming that the system does not have complete cascade channel state information, under the constraint of interruption probability, a robust beam forming design scheme is provided by jointly optimizing active and passive beam forming, and the minimum of system transmitting power is realized;
Figure FDA0003423570000000011
Figure FDA0003423570000000012
Figure FDA0003423570000000013
Figure FDA0003423570000000014
Figure FDA0003423570000000015
wherein the content of the first and second substances,
Figure FDA0003423570000000016
is a transmit beamforming vector of a multi-antenna Access Point (AP) to an mth Information Decoder (IDR),
Figure FDA0003423570000000017
is the signal-to-noise ratio of the mth IDR,
Figure FDA0003423570000000018
is the signal-to-noise ratio, mu, of the kth Energy Harvester (EHR) intercepting the mth IDR informationminIs the minimum signal-to-noise ratio, γ, required for IDRminIs the minimum signal-to-noise ratio threshold, R (p), for the EHR to successfully decode the informationk) Is the minimum threshold for non-linear energy harvesting,
Figure FDA0003423570000000019
representing the maximum outage probability satisfying constraints (1b), (1c) and (1d), the phase shift matrix of the RIS being defined as
Figure FDA00034235700000000110
Figure FDA00034235700000000111
NRISIs the number of reflection units of the RIS;
s3: the method comprises the steps of converting interruption probability constraint into a deterministic form by using a Bernstein-type inequality, converting an original non-convex problem into a convex problem by using a semi-deterministic planning method, and providing an alternative iterative optimization algorithm to obtain a feasible solution of the original problem.
2. The intelligent super-surface assisted terahertz secure communication method according to claim 1, wherein the step S1 specifically comprises:
establishing a RIS-assisted THz safe SWIPT system, which comprises an NTXAP of root antenna, one configuration NRISRIS of the individual reflection units, IDR of the M individual antennas and HER of the K individual antennas; in addition, the controller is connected to the RIS and the AP to acquire phase information required for the RIS, and all receivers can receive only the reflected signal of the RIS assuming that the direct link from the AP to the IDR/EHR is blocked by an obstacle.
3. The intelligent super-surface assisted terahertz secure communication method according to claim 1, wherein the step S2 specifically comprises:
due to the passive characteristic of the RIS, complete CSI is difficult to obtain in an actual wireless portable energy communication (SWIPT) system, so that the consideration of incomplete CSI is more reasonable and effective in a cascade channel AP-RIS-IDR/EHR; in the invention, a statistical CSI error model which has a closer relation with a channel estimation error is adopted, and the aim is to realize the minimization of the total emission of the system by jointly optimizing active and passive beam forming under the constraints of signal-to-noise ratios of IDR and EHR and the interruption probability of nonlinear energy acquisition.
4. The intelligent super-surface assisted terahertz secure communication method according to claim 1, wherein the step S3 specifically comprises:
in view of the non-convexity of the original optimization problem, the invention adopts a Bernstein-type inequality to convert the signal-to-noise ratio of IDR and EHR and the interruption probability constraint of nonlinear energy acquisition into a linear matrix inequality form; in addition, an alternative optimization method based on a semi-definite relaxation technology is utilized to obtain a feasible solution of the problem.
5. An intelligent super-surface assisted terahertz secure communication device, comprising:
the model establishing module is used for establishing an intelligent super-surface assisted terahertz wireless energy-carrying transmission safety communication system model under the nonlinear energy collection model;
an equation construction module, which provides a robust beam forming design scheme by jointly optimizing active and passive beam forming under the constraint of interruption probability and realizes the minimization of system transmitting power on the assumption that the state information of the cascade channel is incomplete;
Figure FDA0003423570000000021
Figure FDA0003423570000000031
Figure FDA0003423570000000032
Figure FDA0003423570000000033
Figure FDA0003423570000000034
wherein the content of the first and second substances,
Figure FDA0003423570000000035
is the transmit beamforming vector from the AP to the mth IDR,
Figure FDA0003423570000000036
is the signal-to-noise ratio of the mth IDR,
Figure FDA0003423570000000037
is the signal-to-noise ratio, μ, of the kth EHR intercepting the mth IDR informationminIs the minimum signal-to-noise ratio, γ, required for IDRminIs the minimum signal-to-noise ratio threshold, R (p), for the EHR to successfully decode the informationk) Is the minimum threshold for non-linear energy harvesting,
Figure FDA0003423570000000038
representing the maximum outage probability satisfying constraints (2b), (2c) and (2d), the phase shift matrix of the RIS being defined as
Figure FDA0003423570000000039
NRISIs the number of reflection units of the RIS;
and the iteration solving module is used for converting the interruption probability constraint into a deterministic form by using a Bernstein-type inequality, converting the original non-convex problem into a convex problem by using a semi-deterministic planning method, and providing an alternative iteration optimization algorithm to obtain a feasible solution of the original problem.
6. The intelligent super-surface assisted terahertz safety communication device according to claim 5, wherein the model building module specifically comprises:
establishing a RIS-assisted THz safe SWIPT system, which comprises an NTXAP of root antenna, one configuration NRISThe RIS of the individual reflection units, the IDRs of the M individual antennas and the EHRs of the K individual antennas, and further, the controller is connected to the RIS and the AP to acquire phase information required for the RIS, and all receivers can receive only the reflected signal of the RIS provided that the direct link from the AP to the IDR/EHR is blocked by an obstacle.
7. The intelligent super-surface assisted terahertz safety communication device according to claim 5, wherein the equation constructing module specifically comprises:
the equation construction module is used for obtaining perfect CSI in an actual SWIPT system due to the passive characteristic of the RIS, so that the consideration of incomplete CSI is more reasonable and effective in a cascade channel AP-RIS-IDR/EHR; in the invention, a statistical CSI error model which has a closer relation with a channel estimation error is adopted, and the aim is to realize the minimization of the total transmission power of the system by jointly optimizing active and passive beam forming under the constraints of signal-to-noise ratios of IDR and EHR and the interruption probability of nonlinear energy acquisition.
8. The intelligent super-surface assisted terahertz safety communication device according to claim 5, wherein the iterative solution module specifically comprises:
in view of the non-convexity of the original optimization problem, the iteration solving module adopts a Bernstein-type inequality to convert the signal-to-noise ratios of IDRs and EHRs and the interruption probability constraint of nonlinear energy acquisition into a linear matrix inequality form, and in addition, an alternative optimization method based on a semi-definite relaxation technology is utilized to obtain a feasible solution of the problem.
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Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20110059705A1 (en) * 2009-09-09 2011-03-10 Nec Laboratories America, Inc. Robust linear precoder designs for multi-cell downlink transmission
US20170250458A1 (en) * 2016-02-29 2017-08-31 Rohm Co., Ltd. Terahertz device and terahertz integrated circuit
CN112073102A (en) * 2020-09-08 2020-12-11 郑州大学 Secure beam forming method and device based on IRS
CN112235026A (en) * 2020-11-06 2021-01-15 郑州大学 Mixed beam design method of MIMO-OFDMA terahertz communication system
CN112632062A (en) * 2020-12-07 2021-04-09 北京航空航天大学 Terahertz frequency band atmospheric transmission characteristic library building method for signal distortion compensation
WO2021103325A1 (en) * 2019-11-28 2021-06-03 东南大学 Millimeter wave/terahertz network large-scale mimo radio transmission method
US20210288698A1 (en) * 2020-03-10 2021-09-16 University Of Electronic Science And Technology Of China Method for Intelligent Reflecting Surface Aided Terahertz Secure Communication System
CN113573293A (en) * 2021-07-14 2021-10-29 南通大学 Intelligent emergency communication system based on RIS
CN113613273A (en) * 2021-08-09 2021-11-05 重庆邮电大学 Steady energy efficiency optimization method of intelligent super-surface auxiliary wireless power supply network
CN113825159A (en) * 2021-09-03 2021-12-21 重庆邮电大学 Wireless energy-carrying communication system robust resource allocation method based on intelligent reflector
US20220407592A1 (en) * 2019-12-26 2022-12-22 Chongqing University Of Posts And Telecommunications Multi-carrier resource allocation method based on wireless-powered backscatter communication network

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20110059705A1 (en) * 2009-09-09 2011-03-10 Nec Laboratories America, Inc. Robust linear precoder designs for multi-cell downlink transmission
US20170250458A1 (en) * 2016-02-29 2017-08-31 Rohm Co., Ltd. Terahertz device and terahertz integrated circuit
WO2021103325A1 (en) * 2019-11-28 2021-06-03 东南大学 Millimeter wave/terahertz network large-scale mimo radio transmission method
US20220407592A1 (en) * 2019-12-26 2022-12-22 Chongqing University Of Posts And Telecommunications Multi-carrier resource allocation method based on wireless-powered backscatter communication network
US20210288698A1 (en) * 2020-03-10 2021-09-16 University Of Electronic Science And Technology Of China Method for Intelligent Reflecting Surface Aided Terahertz Secure Communication System
CN112073102A (en) * 2020-09-08 2020-12-11 郑州大学 Secure beam forming method and device based on IRS
CN112235026A (en) * 2020-11-06 2021-01-15 郑州大学 Mixed beam design method of MIMO-OFDMA terahertz communication system
CN112632062A (en) * 2020-12-07 2021-04-09 北京航空航天大学 Terahertz frequency band atmospheric transmission characteristic library building method for signal distortion compensation
CN113573293A (en) * 2021-07-14 2021-10-29 南通大学 Intelligent emergency communication system based on RIS
CN113613273A (en) * 2021-08-09 2021-11-05 重庆邮电大学 Steady energy efficiency optimization method of intelligent super-surface auxiliary wireless power supply network
CN113825159A (en) * 2021-09-03 2021-12-21 重庆邮电大学 Wireless energy-carrying communication system robust resource allocation method based on intelligent reflector

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
GUANYI ZHANG: "Research on New Grating Structure Based on 340GHz Super Smith-purcell Radiation", 2020 IEEE 21ST INTERNATIONAL CONFERENCE ON VACUUM ELECTRONICS (IVEC) *
MIN HU: "Tunable terahertz radiation from graphene surface plasmon polaritons excited by parallel moving electron beam", 2015 40TH INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER, AND TERAHERTZ WAVES (IRMMW-THZ) *
周儒雅;唐万恺;李潇;金石;: "基于可重构智能表面的移动通信简要综述", no. 06 *

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